1. Field of Invention
The present invention relates to process reactors, and in particular relates to reactors employing process gases and a plasma source.
2. Description of Background Information
Typically, plasma is a collection of charged particles containing approximately equal numbers of positive and negative charge carriers and can be used in certain processing systems which are useful for a wide variety of applications. For example, plasma processing systems are of considerable use in material processing and in the manufacture and processing of semiconductors, integrated circuits, displays and other electronic devices, both for etching and layer deposition on substrates, such as, for example, semiconductor wafers.
Generally, the basic components of such a system include a plasma chamber enclosing a processing region in which plasma is formed and a pumping region connecting to a vacuum port. Other basic components of such a system generally include a wafer supporting chuck, which is connected to an RF power supply in order to accelerate the plasma ions to strike the wafer surface with a desired energy. An additional electrode or RF antenna can be used to produce the process plasma. The chuck is normally cylindrical and flat, supporting a substrate for processing. For efficient use of chamber space, i.e. maximizing gas flow uniformity and minimizing the reactor footprint, process gases are injected above or around the plasma region, and the used gases are removed through an annular passage between the chuck and the sidewall to the vacuum pumping port provided in the lower portion of the vacuum chamber. With a large mass flow rate of processing gases, a large pumping speed for removing the used gases is important to process performance including factors such as the etch rate, high aspect ratio etch, profile figure, damage and contamination. The gas conductance of the annular region often severely restricts the pumping speed delivered to the processing region.
In addition to the need of larger chamber conductance, the need for higher pumping speed at the process operating pressure range, i.e., 5-100 m Torr, is generally required for high density plasma (HDP) etch systems. Plasma vacuum pump systems have been proposed for the process system to provide the required pumping speed for removal of effluent gases, for example.
One aspect of the present invention is to provide a method of pumping particles from a first region containing a plasma to a second region through a passageway having an inlet end and an outlet end. The passageway is defined by an inner wall and an outer wall. The method comprises producing an alternating magnetic field and producing an electric field. The alternating magnetic field extends generally transverse to the passageway. The electric field is produced in a direction generally transverse to the passageway and generally transverse to the magnetic field.
Another aspect of the present invention is to provide a plasma pump that is configured to pump particles from a first region containing a plasma to a second region containing a plasma at a higher pressure. The plasma pump comprises a passageway having an inlet end and an outlet end. The passageway is defined by an inner wall and an outer wall. A magnetic field producing member is constructed and arranged to produce an alternating magnetic field, which extends generally transverse to the passageway. An electric field producing member is constructed and arranged to produce an electric field in a direction generally transverse to the passageway and generally transverse to the magnetic field.
A plasma processing system including the plasma pump described above can-also be provided. The plasma processing system comprises a chamber containing a plasma processing region and a chuck constructed and arranged to support a substrate within the chamber in the plasma processing region. A chamber outlet enables particles within the plasma processing region to exit the chamber to the plasma pump.
Yet another aspect of the present invention is to provide a plasma pump that is configured to pump particles from a first region containing a plasma to a second region containing a plasma at a higher pressure. The plasma pump comprises a passageway having a central inlet region and a peripheral outlet region. The passageway is defined by an inner wall and an outer wall. A substantially radial direction of the passageway extends between the inlet region and the outlet region. A magnetic field producing member is constructed and arranged to produce an alternating magnetic field which extends generally transverse to the radial direction of the passageway. An electric field producing member is constructed and arranged to produce an electric field in a direction generally transverse to the radial direction of the passageway and generally transverse to the magnetic field.
A plasma processing system including the plasma pump described above can also be provided. The plasma processing system comprises a chamber containing a plasma processing region and a chuck constructed and arranged to support a substrate within the chamber in the plasma processing region. A chamber outlet enables particles within the plasma processing region to exit the chamber to the plasma pump.